Automotive exhaust pipes are typically routed along the underbody of a vehicle and may take winding paths between the exhaust manifold, catalytic converter, and muffler depending upon the design and location of other components of the vehicle. In order to avoid obstructions and for underbody packaging purposes, it is often necessary for the exhaust pipe to include one or more bends along its length. Such exhaust pipes can be manufactured in separate sections between at least some of the bends, positioned in an end-to-end axial configuration, and then connected together by a pipe clamp to form an assembled exhaust pipe. In an automotive assembly plant, the first step of this process may be performed while a vehicle is actually flipped upside down, giving an operator access to the underbody. The pipe clamps are typically not tightened until the vehicle is again flipped right side up. As a result, it is not unusual for the loosely-connected exhaust pipe ends and pipe clamps to dislodge when the vehicle is flipped back to its normal orientation, or to become dislodged simply when the vehicle is progressing to a subsequent assembly stage. When this happens, the assembly process is disrupted and consequently becomes less efficient.
In such applications, the pipes are usually positioned and connected together either as a lap joint, with the pipe ends telescopically overlapping each other, or as a butt joint, with the pipe end edges abutting each other. For lap joints, a band clamp is commonly used to clamp the two pipe ends together and is attached over the outer pipe at a location where the two pipes overlap. For butt joints, a pipe coupler is normally used which spans the juncture of the two abutting pipe ends and includes a clamping mechanism that permits it to be securely clamped over both of the two ends. As used throughout this patent, the term “pipe clamp” broadly includes both band clamps and pipe couplers.
In both lap joints and butt joints the integrity of the seal is at least partially dependent upon pipe end positioning. In lap joints, if the pipe ends are overlapped too far, the excess pipe material becomes waste. Conversely, if the pipe ends are not overlapped far enough, an adequate seal may not be provided. For butt joints, an inadequate seal can result if the pipe end edges are not positioned to properly abut each other. A further performance-related consideration involves the seal strength of the clamp over time. It is not uncommon for some clamping mechanisms to experience some degree of decreased sealing performance as the clamp ages. However, designs that rely upon the resilient properties of one or more clamp components to improve the strength of the seal, can oftentimes only be used once. Thus, reusability of the clamp may be limited.